This invention relates to devices for unscrambling, singulating and ending logs.
The invention is used to unscramble bundles of logs and to promote the logs from the bundle to another, usually higher, location. Generally speaking, devices that do this are well known. Such devices are sometimes called indexing apparatus, unscramblers or singulators. The term xe2x80x9csingulatorxe2x80x9d refers to the fact that the devices are usually designed to deliver a single log at a time to an outlet of the device.
Examples of prior art unscrambling and singulating devices are found in U.S. Pat. No. 5,653,570 to Weirathmueller; U.S. Pat. No. 5,257,688 to Fridlund; U.S. Pat. No. 5,423,417 to Redekop and Canadian Patent No. 1,091,611 to Hallstrom.
One form of singulator that is relatively well known comprises a series of steps moving along an incline from an inlet location to an outlet location. Two groups of reciprocating cooperate so as to gradually promote logs toward the outlet. Such devices are typified by Canadian Patent No. 1,277,682 to Ekholm.
Another form of singulator is described in U.S. Pat. No. 5,119,930 to Stelter. The ""930 patent relies on multiple stages of movable quadrants to promote and singulate logs. The top portion of each quadrant presents a log supporting shelf that diminishes in size against a fixed surface as the quadrant moves through an arc so as to limit the number of logs promoted to the next stage.
The foregoing systems each involve step-wise reciprocating motion. Such motion in heavy machinery generates significant noise, and the repetitive contact between parts causes considerable wear.
It is an object of the present invention to provide an alternative yet effective approach to unscrambling and singulating logs.
It is a further object of this invention to provide such a device that is self-cleaning, that automatically ends logs, and in which both noise and wear is reduced in relation to prior art systems.
The present invention provides a series of laterally spaced inclined spiral rolls extending between an inlet location where logs are received in a bundle, and an outlet location at a higher elevation than the inlet location.
The outlet is rearwardly offset in relation to the inlet so that the spiral rolls have a front to back inclination. The spiral rolls of the invention are also inclined sideways, i.e. they define on angle in relation to the feed direction. The spiral rolls comprise a pipe roll and a flange or xe2x80x9cflightxe2x80x9d wrapped around the pipe roll to define a spiral or helix about the length of the pipe roll. The gaps on the pipe roll between successive revolutions of the flight are aligned with the gaps on the adjacent spiral rolls. The series of adjacent gaps across the plurality of spiral rolls defines an elongated log-receiving trough. The spin of the spiral rolls is also synchronized so as to promote the log-receiving trough in an even upward motion. In the area of the infeed, the action of the spiral flights digging into the log bundle assists in dislodging individual logs and urging them into the log-receiving trough.
The resulting device has the advantage of continuous action, thereby avoiding the repetitive loud banging associated with prior art singulators, and reducing wear on the moving parts.
Another advantage of the invention is that the logs are continuously xe2x80x9cendedxe2x80x9d in one direction by the turning action of the spiral rolls. Ending the logs refers to aligning the end of a log against a reference surface. Such ending assists in measuring the logs and in controlling subsequent advancement and cutting operations for the log.
It is a further feature of the invention that the sideways inclination of the spiral rolls allows the logs to more closely abut the face of the helical flights. Without such a sideways angle, the logs would ride on the sharp edges of the flights thus impeding smooth progress of the logs.
Other aspects of the invention will be appreciated by reference to the detailed description that follows and are more particularly defined by the claims.